Question

Which of the following steam turbine is NOT compounded?

• A. De Laval turbine
• B. Curtis turbine
• C. Rateau turbine
• D. Parson's turbine

Hint:

Remember: De Laval = Default. It is the "default" or simplest version with just One stage. Every other famous name on this list (Curtis, Rateau, Parson) is associated with a specific type of multi-stage "Compounding."

Answer 1

The Correct Option is A

Compounding is the method of using multiple stages (sets of nozzles and blades) to absorb the high energy of steam in steps. This reduces the rotational speed of the turbine to manageable levels and improves efficiency. 1. The De Laval Turbine: The

De Laval turbine is the simplest form of an impulse turbine. It is a

single-stage turbine consisting of one set of nozzles and one set of moving blades.

• High Velocity: Because the entire pressure drop occurs in a single set of nozzles, the steam exits at extremely high velocities (often supersonic).

• High Speed: To work efficiently, the rotor must spin at very high speeds (up to 30,000 RPM), which often requires a gearbox to reduce the speed for practical use.

2. Types of Compounded Turbines:

• Curtis Turbine: Utilizes

Velocity Compounding (two or more sets of moving blades with stationary blades in between).

• Rateau Turbine: Utilizes

Pressure Compounding (multiple sets of nozzles and moving blades).

• Parson's Turbine: A multi-stage

Reaction Turbine where pressure drop occurs in both fixed and moving blades.

3. Conclusion: Since the De Laval turbine achieves its entire energy conversion in a single set of blades without any "compounding" stages, it is the correct answer.